Re: [Boost-users] PP: 2 to the power x macro

4 Feb 2010

      2010/2/4 Ravi <lists_ravi@lavabit.com>
...
On Tuesday 02 February 2010 21:29:40 Hicham Mouline wrote:
...
I can't find this left shift operator in Boost.PP.
Do you mean   <<  ?
But then how do I evaluate it in the context of the preprocessor?
Unless I have misunderstood your question (very likely), isn't this what
you
need?
#define POWER2(a) (1<<a)
// Example usage in the context of the preprocessor
#if POWER2(3) == 8
#error "Success, correct calculation"
#else
#error "Failure"
#endif
How about this?

// Must expand to "int foo8;", but it does not.
int BOOST_PP_CAT(foo, POWER2(3));

Roman Perepelitsa.